Oxidation of phenols

ABSTRACT

WHEREIN N IS 1,2, OR 3 AND R IS AN ALKYL GROUP CONTAINING FROM 1 TO 4 CARBON ATOMS.   R-O-(CH2-CH2-O)N-CO-CH3   AN IMPROVED PROCESS FOR THE OXIDATION OF MONO AND DIALKYL PHENOLS WHICH COMPRISES THE COUPLING OF THE PHENOL IN THE PRESENCE OF AN OXYGEN CONTAINING GAS AND A CATALYST SELECTED FROM THE GROUP CONSISTING OF MANGANOUS ACETYLACETONATE, MANGANOUS SILICYCLIDENEIMINE, CERIUM ACETYLACETONATE AND OTHER CHELATES OF MANGANOUS AND CEROUS IONS. THE PROCESS IS SOLVENT SPECIFIC AND HAS BEEN FOUND TO YEILD THE BEST RESULTS IN A SOLVENT WHICH IS A SATURATER ALIPHATIC MONOHYDRIC ALCOHOL CONTAINING FROM 2 TO 10 CARBON ATOMS, AN ESTER OF A SATURATED ALIFROM 4 TO 12 CARBON ATOMS, AN ESTER OF A SATURATED ALIPHATIC MONOHYDRIC ALCOHOL CONTAINING FROM 4 TO 10 CARBON ATOMS AND ACETIC, PROPIONIC, OR BUTYRIC ACID, ETHYLENE GLYCOL DIACETATE, DIETHYLENE GLYCOL DIACETATE, TRIETHYLENE GLYCOL DIACETATE, AND ETHER-ESTERS CHARACTERIZED BY THE FORMULA

US. Cl. 260-396 R 14 Claims ABSTRACT OF THE DISCLOSURE improved processfor the oxidation of mono and dialkyl phenols which comprises thecoupling of the phenol in the presence of an oxygen containing gas and acatalyst selected from the group consisting of manganousacetylacetonate, manganous salicyclideneimine, cerium acetylacetonateand other chelates of manganous and cerous ions. The process is solventspecific and has been found to yield the best results in a solvent whichis a saturated aliphatic monohydric alcohol containing from 2 to carbonatoms, a saturated aliphatic ketone containing from 4 to 12 carbonatoms, an ester of a saturated aliice ' alcohol, isopropyl alcohol,secondary butyl alcohol, ethyl alcohol, n-propyl alcohol, n-butylalcohol, n-amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol,nonyl alcohol, decyl alcohol, methyl isobutyl ketone, methyl ethylketone, methyl propyl ketone, diethyl ketone, dipropyl ketone, propylbutyl ketone, dibu-tyl ketone, butyl amyl ketone, diamyl ketone, amylhexyl ketone, propyl octyl ketone, butyl acetate, amyl acetate, hexylacetate, heptyl acetate, octyl acetate, nonyl acetate, decyl acetate,butyl propionate, amyl propionate, hexyl propionate, heptyl propionate,octyl propionate, nonyl propionate, decyl propion-ate, butyl butyrate,amyl butyrate, hexyl butyrate, heptyl butyrate, octyl butyrate, nonylbntyrate, decyl butyrate, ethylene glycol monoethyl ether acetate,ethylene glycol monomethyl ether acetate, ethylene glycol monopropylether acetate, ethylene glycol monobutyl ether acetate, diethyleneglycol monobutyl ether acetate, diethylene glycol monopropyl etheracetate, diethylene glycol monomethyl ether acetate, diethylene glycolmonoethyl ether acetate, triethylene glycol monoethyl ether acetate,triethylene glycol monomethyl ether acetate, triethylene glycolmonopropyl ether acetate, and triethylene glycol monobutyl etheracetate. Preferred solvents include methyl isobutyl phatic monohydricalcohol containing from 4 to 10 carbon' atoms and acetic, propionic, orbutyric acid, ethylene glycol diacetate, diethyleneglycoldiacetate,;triethylene glycol diacetate, and ether-esterscharacterized by the formula wherein n is 1, 2, or 3 and Ris an alkylgroup containing from 1 to 4 carbon atoms.

This application is a continuation-in-part of US. patent applicationSer. No. .879,540,; 1filed Nov. 24, 1969, now abandoned. e

,This invention concerns an improved process for the oxidation ofmonoalkyl phenols and dialkyl phenols to diphenoquinones and polypehnoxyethers. More particularly, this invention relates to the oxidation of2,6-dialkyl substituted phenols and ortho or para-substituted alkylphenols to diphenoquinones and polyphenoxy ethers.

It is an object of this invention to provide a novel process for theoxidation of 2,6-dialkyl substituted phenols to a variety of quinonesand polymers of the phenoxy ether variety. Y I

It is alsoan 7 ed for the direct oxidation of 2,6-dialkylphenols to thecorresponding tetra-substituted diphenoquinones."

other'objects of this invention will become evident to those skilled inthe art in the following detailed description of the invention.

, In general, this process entails the oxidation of an alkylphenolby anoxygen containing gas in the presence of a particular metal chelate anda particular solvent. The reaction is liquid phase and solvent specificsince only compounds selected from the group consisting of aliphaticmonohydric alcohols containing from 2 to; 10 carbon, atoms, saturatedaliphaticketones containing from v4 to 12 carbon atoms, esters o'f asaturated aliphatic monohydric alcohol containing from 4 to 10 carbonatoms and acetic acid, propionic acid, or butyric acid, ethylene glycoldiacetate, diethylene glycol diacetate, triethylene glycol diacetate,and ether-esters characterized by the formula ing from 1 .to 4 carbonatoms, are effective as solvent.

Illustrative examples of solvents include tertiary amyl object of thisinvention to provide a methketone amyl acetate, methyl n-amyl ketone,ethylene glycol, diacetate, ethylene glycol monoethyl ether acetate,tamyl alcohol, and isopropyl alcohol. The catalysts which have beenfound to be most effective are chelates of cerous and mangnaous ions andin particular those most effective are the acetylacetonate and thesalicylideneimine chelates of these two metal ions.

The process comprises heating the catalysts in the solvent system, withall or a portion of the reactant, to reaction temperature in an oxygenatmosphere, and upon reaching reaction temperature injecting theremaining alkylphenol, if any, into the system. These catalysts whenmixed in the solvent do not totally dissolve but rather an equilibriumbetween dissolved catalysts and catalysts in suspension is formed. Ingeneral the temperature range at which this process is carried out isfrom about 30 to about 100 C. and the catalyst concentration is afraction of a mol per mol of reactant. A preferred temperature range foroptimizing the yield would be from about 40 C. to about 80 C., with thecatalyst concentration from about 0.2 to 0.0025 mol per mol of reactant.After the reaction has gone to completion the products of the reaction;namely, a diphenoquinone derived from an alkylphenol and/ or apolyphenoxy ether of the alkylphenol are separated by the followingprocedure: the polyphenoxy ether which is soluble in the solvent isseparated from any diphenoquinone and the catalyst by filtration andthen a washing of the filter cake this oxidation reaction can be anyalkylphenol. The alkyl groups where the phenol is dialkyl should be inthe 2,6- position but need not be symmetrical groups. Examples of thephenols used in carrying out this process are compounds such as2,6-xylenol, 2-methyl-6-butylphenol, 2,6-ditertiarybutylphenol,2,6-disecondarybutylphenol, 2,6- diisopropylphenol,2,6-diisobutylphenol, 2-octyl-6-methylphenol, 2-isobutyl-6dodecylphenol, 2-ethyl-6-methylphenol, 2,6-didecylphenol,para-isopropylphenol, orthomethylp'henol, meta-propylphenol, andpara-methylphenol. Where an alkylphenol has been substituted with anonalkyl moiety it has been found that the reaction will not 3 4 readilyproceed, thus phenols such as 2-methyl-6-chlorothe solvents useful forthis process and with the various phenol or 2-methyl-6-aminophenol arenot satisfactory catalysts found to be active for this oxidation. Thesereactants for the oxidation reaction of the instant specifica runs arelisted in Table I. The process procedures used tion. In a preferredgroup of alkyl and dialkyl phenols in these examples are as follows:

the alkyl group contains at most five carbon atoms. (A) A specificamount of solvent, the particular cata- In a preferred embodiment ofthis inveniton the catalyst and the phenol are placed in a scalablereaction lyst is limited to the following chelates: manganousacetylvessel which can be stirred by a magnetic stirrer or otheracetonate and manganous salicylideneimine and the solmeans. The reactionvessel is then purged with an oxygen vent is tertiary amyl alcohol,methyl isobutyl k t n stream until the atmosphere within the vessel isessentialethylene glycol diacetate, amyl acetate, methyl n-amyl yg Heatis s PP 111ml the feactlcfin system acetate, and ethylene glycol th l thacetate or is at the desired reaction temperature. The reaction startsisopropyl alcohol. The reaction is carried out at a temas soon astemperature is reached and Proceeds to rature f fro 40 t 30 (3, pletion.Completion is indicated by no further oxygen The products of thisreaction are dependent upon the consumpholl) particular phenol used inthe reaction, the particular (B) A Solvent catalyst and about 40 f P Fcatalyst employed and also the Solvent employed. In of the phenol to bereacted are placed in a reaction vessel according to procedure (A) andthe vessel is oxygen flushed. The reaction system is then heated totemperature. The remaining phenol is added in increments of about 20weight percent of the total phenol charge polyphenoxy ether usingmanganous acetylacetonate m at about 3/2 hour, about hour and about 1%hours tertiary amyl l 714% conversion to the f after the reactiontemperature is reached. The reaction phenoxy ether is obtained. However,when methyl isois then allowed to proceed to completion.

butyl ketone is used instead of the tertiary amyl alcohol 0 Thisprocedure i identical to procedure above with the same catalyst the p ypy ether is cept the time intervals for addition of the remaining formedat 79% conversion at 100% yield. Furthermore, phenol are approximately/2 hour, /6 hour and 1 /6 the solvent-catalyst system does not catalyzeoxidation of hours after reaction temperature is reached.

TABLE I.EXAMPLES 1-17 other words the solvent-catalyst are specificsystems causing the reaction to proceed to a particular product mix.Thus, during the oxidation of ortho-methylphenol to a Percent conversionReactant t0- Reaction Catalyst Percent Ether,

unre- Temp., Time/ 02, used Dlphenoapproxi- ML Type, Mmols Type Mmolsacted c. hours Mmols qulnone mate 10 MI1(AA;z 2.0 2,6-xy1enol 15 13.5 653.5 6.55 65 11.0 10 Mn(AAz 2. 15 5.0 7.73 39.6 59.0 10 Mn(AA)2 2. 12 5.57.72 76.3 23.0 10 Mri(AA)z 2. 15 14 65 1 5.8 61 23.0 10 Mn(AA)z 2. 1229.4 55 5 /4 4.55 59 11.0 10 Mn(AA)z 1. 15 15.4 65 5 6.6 78 Trace 10Mn(AA)| 0. 15 23.5 65 5 5.67 69.5 Trace 100 Mn(AA)i 10. 150 65 5% 81.081.0 18.9 100 Mn(AA)a 10. 150 19 65 6 67.5 76 4.0 10 Pd(AA)g 2. 15 10065 4 100 Mn(AA): 5. 150 23.4 65 6% 86.1 Trace 10 Mn(S 2.0 15 65 3% 7.2761 10 Ce(AA)a 2.0 15 35.5 65 3 4.57 25 10 Oe(AA)a 2.0 15 33.6 75 5 5.024 A 10 Ce(AA)s 2.0 15 68.3 75 5% 2.28 32 16/A 10 Mn(AA)1 2.0 d 15 28.665 5.0 6.34 71.4 17/A....---- TAA 10 M.n(AA)g 2.0 Para-150p 15 65.5 706.0 4.06 30.0

pylphenol.

1 TAA (tertiary amyl alcohol), IPA(isopropyl alcohol), SBA(secondarybutyl alcohol), MIBK(methyl lsobutyl ketone). ace: lMn(tAA)tz=Manganousacetylaeetonate, Mn(sallm)=manganous salieylldene imine, Ce(AA) =ceriumacetylacetonate, Pd(AA)z=pallad1um y ace ona e.

all phenols in the same manner, thus para-isopropylphenol In the abovetable, showing the results and the charges does not yield a highmolecular weight polyphenoxyether of reactants for each example, notonly is the product as rather a dimer trimel 0 the Phenol is thereaction 50 percent conversion given but also where applicable theProduct Examples of the Products of this reaction include percent of theunreacted xylenol or other phenol is tabucompounds such as Z y p qlated. Also included is a run, listed as Example 10, showy yl p q P Y(ing that chelates of ions other than manganous and cerous methylphenoxy)ether, P Y( P QPY P Q Y) ether; 55 are not effective in this reaction,thus Example 10 is out- -p py y '-P py y p q and side the scope of thesubject ingention.

P y( fi- Y P Y) therthe p yp y- The following procedure is used inExamples 18 through ether Products the number of reheating units Ingeneral 24: 1.83 grams of 2,6-xylenol, 0.496 gram of manganous W111 befrom 2 to about 30 dspshdlng 11P011 the p l acetyl-acetonate, and 10 ml.of the indicated solvent are Phenol used: a Preferred mofie of reactionadded to a reactor tube. The reactor is a 25 ml. test tube the phenolswill be limited to 2,6-su bst1tuted dialkyli h a 2% Standard taper j iat h Th reactor i Phenols Wherelll the alkyl P contalns 110 more thanheated byan Instatherm coating. Temperature is controlled about 5 carbona by a thermistor in a well in the top of the reactor, which TheCompounds made y thls Process have many uses, also contains a gas inlettube. Oxygen is introduced from for instance, the diphenoquinones whichare prepared by the above process upon hydrogenation form valuablebisphenols which can be readily used to make polyester compounds. Thepolyphenoxyethers prepared by the above process can be used as monomersin preparing polyester a buret which automatically maintains pressure as3 to 5 mm. above atmospheric pressure. The reactor is flushed withoxygen at room temperature. The heat is turned on, and pressure isreleased as temperature rises. The temproducts or have been furthercondensed with alkylperaiture mamtflmed at The f i is on phenols to givehigh molficular Weight polymer resins aVibrarnixer which produces afast, swirling action causcontaining polyether linkages, both resinsbeing useful ing a thin film of liquid to more rapidly cover the reactorin castings and other applications where thermosetting surface andthereby give good Oxygen-liquid Contact After resins have foundpreference in the industry. one hour reaction, the reactor is flushedwith nitrogen To illustrate the results of this reaction various runs dco d to room temperature. The contents of the rewere made usingdifferent alkyl and dialkyl phenolsin 5 actor are filtered, and the redtetramethyldiphenoquinone 5 residue is washed with methanol and dried at60 C. The results obtained are shown in Table II.

n-Amy acetate 30 86 Ethylen glycol ethyl ether acetate.. 3 98 1 Reactiontime is ten minutes.

Having thus described my invention, I claim:

1. A process for the oxidation of alkyl phenols which comprises heating,to a reaction temperature .from 30 C. to about 100 C., a slurrycomprising unsubstituted alkyl phenol selected from the group consistingof monoalkyl phenols and 2,6-dialkyl phenols, a solvent for the alkylphenol selected from the group consisting of saturated aliphaticmonohydric alcohols containing from 2 to 10 carbon atoms, saturatedaliphatic ketones containing from 4 to 12 carbon atoms, esters of asaturated aliphatic monohydric alcohol containing from 4 to 10 carbonatoms and acetic acid, propionic acid, or butyric acid, ethylene glycoldiacetate, diethylene glycol diacetate, triethylene glycol diacetate,and ether-esters characterized by the formula R0 (CHaCHzOh CH:

wherein n is l, 2, or 3 and R is an alkyl group containing from 1 to 4carbon atoms, and a catalyst selected from the group consisting ofmanganous acetylacetonate, cerous acetylacetonate, manganoussalicylideneimine, and cerous salicylideneimine, while simultaneouslycontacting said slurry with an oxygen containing gas so as to intimatelycontact the oxygen, the catalyst, and the alkyl phenol.

2. A process of claim 1 wherein the alkyl group of said alkyl phenolcontains from 1 to 5 carbon atoms.

3. A process according to claim 1 wherein the catalyst is manganousacetylacetonate.

4. A process according to claim 1 wherein the catalyst is cerousacetylacetonate.

5. A process according to claim 1 wherein the solvent is selected fromthe group consisting of methyl isobutyl ketone, amyl acetate, methyln-amyl ketone, ethylene glycol diacetate, ethylene glycol monoethylether acetate, tertiary amyl alcohol, and isopropyl alcohol, thetemperature of reaction is from 35 C. to 100 C., and the amount ofcatalyst employed is from 0.2 to 0.0025 mol per mol of 50 reactant.

6. A process according to claim 5 wherein the catalyst is manganousacetylacetonate.

7. A process according to claim 6 wherein the alkyl phenol is a2,6-dialkyl substituted phenol wherein the 5 alkyl side chains containfrom 1 to 5 carbon atoms.

8. A process according to claim 1 wherein only a portion of the alkyl ordialkyl phenol is added to the slurry initially and the remainder isadded incrementally over the course of the reaction.

9. A process according to claim 8 wherein the initial portion of saidalkyl or di-alkyl phenol is up to about 40 weight percent of the totalphenol to be reacted.

10. A process according to claim 9 wherein said catalyst concentrationis from 0.2 to about 0.0025 mol per mol of reactant.

11. A process of claim 1 wherein the solvent is selected from the groupconsisting of saturated aliphatic monoalcohols containing from 2 to 10carbon atoms and methyl isobutyl ketone.

12. A process of claim 11 wherein the alkyl group of said alkyl phenolcontains from 1 to 5 carbon atoms.

13. A process of claim 12 wherein the solvent is selected from the groupconsisting of isopropyl alcohol, secondary butyl alcohol, tertiary amylalcohol, and methyl isobutyl ketone, the temperature of reaction is from35 C. to 100" C., and the catalyst concentration is from 0.2 to 0.0025mol per mol of reactant.

14. A process of claim 11 wherein the catalyst is manganousacetylacetonate or cerous acetylacetonate.

References Cited UNITED STATES PATENTS OTHER REFERENCES DieMahromolekulare Chemie, 105 (1967), pp. 277- 79.

I.A.C.S., :25, Dec. 4, 1968. PP. 7134-35.

VIVIAN GARNER, Primary Examiner US. Cl. X.R.

260-47 ET, 613 R "UNITED ,STATESPATENT. OFF-ICE- -J T E OF" CORRECTIONPATENT NO. "3,784,575

DATED 1; January 8, 197-4 INVENTOR(S) Thomas F. Rutledgelt is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below: i y Y Column 4 line 55,'"ingention" should read invention Column 4, line 61, 'Fbyan" shouldread by an Column -5, TABLE II, under the heading '"Solvent" I"Diisobuty ketone Y Isobutyl hepty ketone Methy n-amy ketone I Ethylenevglyco diacetate n-Amy acetate Ethylen glycol ethyl ether acetate shouldread Y Diisobutyl ketone' I Isobutyl h-eptyl ketone Methyl n-amyl ketone1 Ethylene glycol diacetate n-Amyl acetate Ethylene glycol ethyl etheracetate Column 5, TABLE II, under the heading "Percent conversion" lastnumber cited "3" should read 36 Signed and sea led this 20th day of May1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C.v MASON I I Commissioner of Patents AttestingOfficer and Trademarks

